The present invention relates to a device and method for repairing pipe, such as underground sewer pipe and the like.
Prior methods for repairing damaged pipe lines include moving a liner tube impregnated with a liquid material capable of curing and hardening to the position within the pipe where the damaged portion is located. The liner tube is urged in an outward radial direction into contact with the pipe line being repaired and the liquid material impregnating the liner tube is permitted to cure and harden. The liner tube forms an interior liner in the pipe for the pipe line being repaired.
On some occasions lateral pipe lines are connected to main pipe lines. Often damage occurs at the junction between the lateral pipe line and the main pipe line. T-shaped or Y-shaped liner tubes have been utilized to fit within the junction between the lateral pipe line and the main pipe line. Liner tubes form a T-shaped or Y-shaped liner after hardening to the interior of the junction between the lateral pipe line and the main pipe line.
Ground water outside the lateral pipe line and the main pipe line infiltrates through the damaged portion of the pipe line and migrates between the liner tube and the pipe line to a point where it can enter the pipe line. In order to prevent this infiltration of ground water, attempts have been made to adhere the liner tube to the interior surface of the pipe line being repaired, whether it is a single straight pipe line or a T-shaped or Y-shaped pipe line.
However, considerable difficulty has been encountered in attempting to obtain an adhesive bond between the liner tube and the interior of the pipe being repaired. The interior of the pipe being repaired is often greasy or oily even after high pressure water jetting is performed. Attempts have been made to wash the interior of the pipe line with some success, but washing the interior of the pipe line is often only partial and not reliable. Furthermore, in some types of pipes, such as polyethylene pipes, an adhesive bond cannot be maintained between the resin impregnated liner tube and the polyethylene pipe even if the pipe is free from grease and oils.
Even in those instances where the interior of the pipe line is suitable for accepting a liner, shrinkage of the liner can occur, which creates a gap that allows ground water to flow around the liner and eventually infiltrate the pipe line. For example, thermoset resins are used in cured-in-place pipe applications to form the liner to the interior of the pipe line. These thermoset resins tend to shrink during the curing process, thus creating a gap between the liner and the pipe. Even the slightest shrinkage in the liner can be problematic.
U.S. Pat. No. 6,994,118 addresses some of these problems in the art. The present invention constitute improvements and additions to the earlier disclosure.
A primary object of the present invention is the provision of an improved device and method for repairing pipe by using hydrophilic seals or other impermeable compressible materials.
A further object of the present invention is the provision of a device and method for preventing ground water from infiltrating a pipe line near the juncture between a main pipe line and a lateral pipe line.
A further object of the present invention is the provision of a device and method for repairing a section of a pipe and preventing entry of ground water from a damaged portion of the pipe being repaired.
A further object of the present invention is the provision of a device and method for repairing the juncture between a main pipe line and a lateral pipe line which uses a hydrophilic band or similar article of impermeable compressible material positioned between the main pipe line and the liner around the opening that connects the main pipe line to the lateral pipe line.
A further object of the present invention is the provision of a device and method for repairing the juncture between a main pipe line and a lateral pipe line which uses a hydrophilic gasket or gasket of similar impermeable compressible material that seals against entry of ground water at the juncture between the pipe lines.
A further object of the present invention is the provision of a device and method for repairing pipe using hydrophilic seals and the like which is economical to manufacture, durable in use, and reliable in operation.